United Devices credit system
This is the original description for the discontinued United Devices point system: Points are based upon the strength of your machine(s), measured against World Community Grid Comparison Device. First, the strength of your participating machine(s) is calculated by measuring the following parameters of your machine against World Community Grid Comparison Device: * CPU Power: The software periodically runs diagnostic tests to establish the processing power of your hardware configuration. These values are averaged and then divided by the CPU-Power value of World Community Grid Comparison Device. The averaged value is then multiplied by the run time used to complete the work unit and return the results to World Community Grid Servers. * Random Access Memory (RAM): The software recognizes the amount of RAM in your hardware configuration. Each time the software starts, it detects any changes to the amount of installed RAM. This value is divided by the RAM value of World Community Grid Comparison Device. The result of this calculation is then multiplied by the run time used to complete the work unit and return the results to World Community Grid Servers. * Hard Disk Storage: On your preferences page, you set the megabytes of hard disk space allocated and available to World Community Grid projects. The lesser of the amount of hard drive space allocated and the amount of total space available on your hard drive partition, is divided by the Hard Disk Storage value of World Community Grid Comparison Device. The result of this calculation is then multiplied by the run time used to complete the work unit and return the results to World Community Grid Servers. * Effective Upstream Throughput: The software runs a diagnostic test on a regular basis that measures the upstream throughput of your hardware configuration, when communicating with World Community Grid Servers. These values are averaged, and the result is divided by the Effective Upstream Throughput value of World Community Grid Comparison Device. The result of this calculation is then multiplied by the run time used to complete the work unit and return the results to World Community Grid Servers. The final values for all four parameters are weighted, totaled, and factored to generate a whole number of points greater than or equal to 1 for each result returned. While any individual parameter can overachieve the corresponding parameter for World Community Grid Comparison Device by any level, no work unit completed by any machine will earn more than twice the total number of points World Community Grid Comparison Device would earn for that same work unit. Note: The slightest variance in any of the five parameters coupled with the inherent differences across multiple applications and work units within one project will result in different point values being assigned per work unit completion. Criticism In practice, the system had a number of weaknesses. World Community Grid ignored the network speed metric, since it bore no relation to actual performance. The hard disk metric used assigned space, not space used or available. So, it favoured members who set their preference to the maximum, but again, bore no relation to actual performance. CPU power, the one metric that was really relevant to computing performance, caused fast computers to max out the entire score (capped at twice the score of the comparison device). As computers got faster, this limit quickly became ridiculous. Also, the benchmarks did not necessarily accurately represent average conditions, since they were affected by other programs running at the same time. Finally, the runtime measurement (a critical component of the credit calculation) was fatally flawed, because it represented elapsed (wall-clock) time, rather than CPU time. This made it very easy to game the system. Transition to BOINC When World Community Grid added support for BOINC clients in 2005, points earned with the BOINC system were scaled to match (on average) points earned with the United Devices system. This scaling is still in effect. World Community Grid plan to rescale the BOINC points to their original values, and at the same time retrospectively scale the United Devices points to match the BOINC system, and import the United Devices credit permanently into the BOINC system. No date has been set for this adjustment.